Related papers: First-principles study of phonon anharmonicity and…
Harnessing the power of low-dimensional materials in thermal applications calls for a solid understanding of the anomalous thermal properties of such systems. We analyze thermal conduction in one-dimensional systems by determining the…
We have investigated the anisotropic thermal expansion of graphite using ab-initio calculation of lattice dynamics and anharmonicity of the phonons, which reveal that the negative thermal expansion (NTE) in the a-b plane below 600 K and…
Motivated by the recent progress on the holographic dual of the extended thermodynamics for black holes in anti-de-Sitter (AdS) space, we investiggate the hologrphic thermodynamics for the five-dimensional neutral Gauss-Bonnet AdS black…
We study the structural and vibrational properties of the high-temperature superconducting sulfur trihydride and trideuteride in the high-pressure $Im\bar{3}m$ and $R3m$ phases by first-principles density-functional-theory calculations. On…
Anharmonic effects are widely believed to be the primary cause of the overestimation of superconducting transition temperatures of yttrium hydrides YH$_6$ and YH$_9$ in theoretical predictions. However, prior studies indicate that…
Despite many of the applications of graphene rely on its uneven stiffness and high thermal conductivity, the mechanical properties of graphene, and in general of all 2D materials, are still elusive. The harmonic theory predicts a quadratic…
In the present work we explain the anomalous behavior of the attenuation of the longitudinal acoustic phonon in GaAs as a function of the phonon energy $\omega$ in the sub-THz domain. These attenuations along the [100] direction show a…
Group theoretical aspects of the three temperature-dependent and temperature-reversible experimentally observed phase transitions in the KNbO3 crystal (cubic-tetragonal, tetragonal-orthorhombic, orthorhombic-rhombohedral) in the framework…
After a review of temperature-dependent experimental x-ray absorption near-edge structure (XANES) and related theoretical developments, we present the Al K-edge XANES spectra of corundum and beryl for temperature ranging from 300K to 930K.…
A unified approach is used to study vibrational properties of periodic systems with first-principles methods and including anharmonic effects. Our approach provides a theoretical basis for the determination of phonon-dependent quantities at…
We present three Monte Carlo models for the propagation of athermal phonons in the diamond absorber of a composite semiconducting bolometer `Bolo 184'. Previous measurements of the response of this bolometer to impacts by $\alpha$ particles…
We consider the phonon contribution to the bulk viscosities $\zeta_1, \zeta_2$ and $\zeta_3$ of a cold relativistic superfluid. We assume the low temperature $T$ regime and that the transport properties of the system are dominated by the…
$\beta-Ga_2O_3$ is a promising material candidate for next-generation high power devices even as its low thermal conductivity ($\kappa$) limits utilization due to an inability to sufficiently dissipate heat. Despite its importance, a…
The dynamic structures of the cubic and tetragonal phase in BaTiO3 and its dielectric response above the cubic-to-tetragonal phase transition temperature (Tp) are studied by first-principles molecular dynamics (MD) simulation. It's shown…
Noise from material defects at device interfaces is known to limit the coherence of superconducting circuits, yet our understanding of the defect origins and noise mechanisms remains incomplete. Here we investigate the temperature and…
The layered semiconductor SnSe is one of the highest-performing thermoelectric materials known. We demonstrate, through a first-principles lattice-dynamics study, that the high-temperature Cmcm phase is a dynamic average over lower-symmetry…
Decoherence of a flux qubit due to inelastic scattering of thermal phonons by the qubit is studied. The computed decoherence rates contain no unknown constants and are expressed entirely in terms of measurable parameters of the qubit. The…
We study the effects of anharmonicity on the physics of the Holstein model, which describes the coupling of itinerant fermions and localized quantum phonons, by introducing a quartic term in the phonon potential energy. We find that the…
We use a hybrid strategy to obtain anharmonic frequency shifts and lifetimes of phonon quasi-particles from first principles molecular dynamics simulations in modest size supercells. This approach is effective irrespective of crystal…
A simulation study of negative thermal expansion in Y2W3O12 was carried out using calculations of phonon dispersion curves through the application of density functional perturbation theory. The mode eigenvectors were mapped onto flexibility…